[Freeswitch-users] T.38 SDP not forwarded by FS in t38-passthru mode

9 Feb 2012

      I have trouble with fax because the INVITE generated by FS doesn't contain
the image part.

In my profile I have set:

<param name="t38-passthru" value="true" />

and the dialplan (simplified)  is:

<action application="export" data="t38_passthru=true"/>
<action application="bridge" data="sofia/external/xxxx" />

but when is received an INVITE with SDP:

v=0
o=- 2598299616 0 IN IP4 213.204.31.103
s=session
t=0 0
m=audio 4640 RTP/AVP 18 8 96
c=IN IP4 213.204.31.32
a=rtpmap:18 G729/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:96 telephone-event/8000
m=image 4642 udptl t38
c=IN IP4 213.204.31.32
a=T38FaxVersion:0
a=T38MaxBitRate:14400
a=T38FaxUdpEC:t38UDPRedundancy
a=T38FaxRateManagement:transferredTCF

is generated in the outbound leg an SDP:

   v=0
   o=FreeSWITCH 1328751960 1328751961 IN IP4 217.19.146.173
   s=FreeSWITCH
   c=IN IP4 217.19.146.173
   t=0 0
   m=audio 31196 RTP/AVP 18 8 0 101 13
   a=rtpmap:101 telephone-event/8000
   a=fmtp:101 0-16
   a=ptime:20

without image part.

Here the log:

http://pastebin.freeswitch.org/18333

Any advice?

[Freeswitch-users] T.38 SDP not forwarded by FS in t38-passthru mode

Stephen Wilde